Synthesis of Bi 2 Se 3 Nanosheets with Applications in Photoelectrochemical Photodetectors

As a typical topological insulator, bismuth selenide (Bi 2 Se 3 ) has attracted significant attention due to its excellent piezoelectric and thermoelectric properties. However, the photoelectric conversion performance of Bi 2 Se 3 for potential applications in photodetection still largely remains an uncharted territory of research. In this work, two‐dimensional Bi 2 Se 3 nanosheets (NSs) with hexagonal shape were prepared by a hydrothermal strategy, and their photo‐response properties were systematically investigated using a photoelectrochemical‐type photodetector. The results show that Bi 2 Se 3 NSs can exhibit a significant photo‐response in alkaline electrolytes and possess excellent long‐term cycling stability (with an attenuation of 1.98% after 2000 cycles). Furthermore, a stable spectral response ranging from 334 to 578 nm has been achieved with a distinct response enhancement in the weak‐ultraviolet range. Through this initial exploration work, we anticipate that the Bi 2 Se 3 NSs hold great potential for photodetection and also for novel optoelectronic devices with high performance.